Re: [PATCH] x86/EISA: Use memremap() to probe for the EISA BIOS signature

[Christoph Hellwig]

On Sat, Aug 24, 2024 at 11:17:10PM +0100, Maciej W. Rozycki wrote:
> -	void __iomem *p;
> +	void *p;
>  
>  	if ((xen_pv_domain() && !xen_initial_domain()) || cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
>  		return 0;
>  
> -	p = ioremap(0x0FFFD9, 4);
> +	p = memremap(0x0FFFD9, 4, MEMREMAP_WB);
>  	if (p && readl(p) == 'E' + ('I' << 8) + ('S' << 16) + ('A' << 24))
>  		EISA_bus = 1;

readl requires and __iomem pointer.  If this is just a memory region you
can and should directly dereference the address instead.

Note that sparse will complain about the above as well.